Improved bandwidth of a 2 THz hot-electron bolometer heterodyne mixer fabricated on sapphire with a GaN buffer layer. (21st May 2019)

• Record Type: Journal Article
• Authors: Antipov, S; Trifonov, A; Krause, S; Meledin, D; Kaurova, N; Rudzinski, M; Desmaris, V; Belitsky, V; Goltsman, G
• Is Part Of: Superconductor science & technology. Volume 32:Number 7(2019:Jul.)
• Publication Date: 2019-05-21
• Subjects: HEB -- GaN buffer layer -- gain and noise bandwidth; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ab137b
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We report on the signal-to-noise and gain bandwidth of a niobium nitride (NbN) hot-electron bolometer (HEB) mixer at 2 THz fabricated on a sapphire substrate with a GaN buffer layer. Two mixers with different DC properties and geometrical dimensions were studied and they demonstrated very close bandwidth performance. The signal-to-noise bandwidth is increased to 8 GHz in comparison to the previous results, obtained without a buffer-layer. The data were taken in a quasi-optical system with the use of the signal-to-noise method, which is close to the signal levels used in actual astrophysical observations. We find an increase of the gain bandwidth to 5 GHz. The results indicate that prior results obtained on a substrate of crystalline GaN can also be obtained on a conventional sapphire substrate with a few micron MOCVD-deposited GaN buffer-layer.